# Timeline for How should I model exact 90-degree rotations in 3D?

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Oct 31 '11 at 21:33 comment Ah, my linear algebra is so rusty.
Oct 31 '11 at 20:49 comment That should work, yes. Note that, since these matrices are orthogonal, their inverse is equal to their transpose.
Oct 31 '11 at 20:07 comment Thanks, this sounds pretty good. When you say a multiplication table, you mean a lookup table where one index is the previous orientation (24 possibilities) and the other index is the 90-degree rotation (6 possibilities), and the value in each cell is the resulting orientation (24 possibilities)? I guess the part of this that seems complicated is mapping the 24 different orientations to/from a linear value. I like the idea of 3x3 integer matrices. But I'm not sure how to use those to query whether a cell is connected in a given direction. Use the inverse matrx to map that direction backwards?
Oct 31 '11 at 19:20 history answered